Wiring board and process for producing the same

Abstract

A wiring board with microstrip structure has: a first conductor layer that is provided with conductor wirings to be connected to a semiconductor chip in its external terminal (bonding pad); a second conductor layer that is provided with a conductor pattern connected through a via to a ground wiring, for supplying a power supply of ground potential to the semiconductor chip; and a third conductor layer that is provided with a power supply terminal connected through a via to a power supply wiring for supplying an operation power supply of a potential other than the ground potential to the semiconductor chip, a signal terminal connected through a via to a signal wiring for transmitting an electric signal, and a ground terminal connected through a via to the conductor pattern in the second conductor layer.

1. A process for producing a wiring board, comprising the steps of:
 forming a first conductor film on a first main surface of a first insulating substrate and forming a second conductor film on a second main surface of the first insulating substrate remote from the first conductor film; 
 forming a first via hole at a predetermined position of the first insulating substrate from the second conductor film side; 
 forming a third conductor film on the surface of the second conductor film and within the first via hole; 
 etching the second conductor film and the third conductor film to form a conductor pattern having openings at predetermined positions; 
 forming a fourth conductor film on the surface of the conductor pattern through a second insulating substrate; 
 forming, from the fourth conductor film side, a second via hole, which extends through the second insulating substrate to the conductor pattern, and a third via hole which extends through the second insulating substrate and the first insulating substrate to the first conductor film; 
 forming a fifth conductor film on the surface of the fourth conductor film and within the second via hole and the third via hole; 
 etching the first conductor film to form a conductor wiring to be connected to an external terminal (a bonding pad) of a semiconductor chip; and 
 etching the fourth conductor film and the fifth conductor film to form a connection terminal to be connected to the conductor wiring or the conductor pattern through the via. 
 
   
   
     2. The process according to  claim 1 , wherein the second via hole and the third via hole are simultaneously formed by using a laser beam which can selectively etch the insulator. 
   
   
     3. A process for producing a wiring board, comprising the steps of:
 forming a first conductor film on a first main surface of a first insulating substrate and forming a second conductor film on a second main surface of the first insulating substrate remote from the first conductor film; 
 forming a first via hole at a predetermined position of the first insulating substrate from the second conductor film side; 
 forming a third conductor film on the surface of the second conductor film and within the first via hole; 
 etching the second conductor film and the third conductor film to form a conductor pattern having openings at its predetermined positions; 
 forming a fourth conductor film through a second insulating substrate on the surface of the conductor pattern formed by etching the second conductor film and the third conductor film; 
 forming, from the fourth conductor film side, a second via hole which extends through the second insulating layer and the first insulating layer to the first conductor film; 
 forming a fifth conductor film on the surface of the fourth conductor film and within the second via hole; 
 etching the fourth conductor film and the fifth conductor film to form a conductor pattern having openings at its predetermined positions; 
 forming a sixth conductor film through a third insulating substrate on the conductor pattern layer formed by etching the fourth conductor film and the fifth conductor film; 
 forming, from the sixth conductor film side, a third via hole, which extends through the third insulating layer and the second insulating layer to the conductor pattern formed by etching the second conductor film and the third conductor film, a fourth via hole, which extends through the third insulating layer to the conductor pattern formed by etching the fourth conductor film and the fifth conductor film, and a fifth via hole which extends through the third insulating layer, the second insulating layer, and the first insulating layer to the first conductor film; 
 forming a seventh conductor film on the surface of the sixth conductor film and within the third via hole, the fourth via hole, and the fifth via hole; 
 etching the first conductor film to form a conductor wiring to be connected to an external terminal (a bonding pad) of a semiconductor chip; and 
 etching the sixth conductor film and the seventh conductor film to form a connection terminal to be connected through the via to any one of the conductor pattern formed by etching the conductor wiring, the second conductor film, and the third conductor film and the conductor pattern formed by etching the fourth conductor film and the fifth conductor film. 
 
   
   
     4. The process according to  claim 3 , wherein the third via hole, the fourth via hole, and the fifth via hole are simultaneously formed by using a laser beam which can selectively etch the insulator.